Physical Health Decline After Chemotherapy or Endocrine Therapy in Breast Cancer Survivors

Women with a history of breast cancer (BC) experience greater physical health decline compared with age-matched women without cancer. However, whether this decline differs in patients who received chemotherapy and endocrine therapy is not well understood.

To investigate physical health decline in BC survivors who received chemotherapy or endocrine therapy compared with age-matched women without cancer.

This prospective cohort study was conducted as part of the Cancer Prevention Study-3, a prospective US cohort study that enrolled participants in 35 states, the District of Columbia, and Puerto Rico between 2006 and 2013. Follow-up for this analysis was through April 1, 2020. Statistical analyses were conducted between May 2023 and December 2024. Female participants diagnosed with nonmetastatic BC who returned a survey at least 90 days after their diagnosis were matched on age and year of survey return with up to 5 women without cancer.

Cancer status and treatment information.

Outcomes of interest were measures of physical health, assessed using the Patient-Reported Outcomes Measurement Information System Global Health Scale instrument. Linear regression was used to estimate associations (β) and 95% CIs of treatment with physical health.

This analysis included 2566 individuals diagnosed with BC and 12 826 age-matched women without cancer. Median (IQR) age at diagnosis was 56.3 (49.9-61.9) years. Of women with BC, 1223 (47.7%) received endocrine therapy, 276 (10.8%) received chemotherapy, and 634 (24.7%) received both. Compared with women without cancer, there was a greater physical health decline within 2 years of diagnosis for BC survivors receiving endocrine therapy (β = -1.12; 95% CI, -1.64 to -0.60), chemotherapy (β = -3.13; 95% CI, -4.19 to -2.07), or both (β = -3.26; 95% CI, -3.97 to -2.55). The decline among endocrine therapy users was restricted to women receiving aromatase inhibitors. More than 2 years after diagnosis, the decline was only observed in women who received chemotherapy.

In this cohort study of 15 392 BC survivors and age-matched women without cancer, BC survivors who received chemotherapy had a long-lasting physical health decline, unlike survivors who received endocrine therapy without chemotherapy. Further studies are needed to confirm these results and to better understand the health consequences of these treatments.